Modular electrical therapy device

ABSTRACT

A therapeutic electrode component includes a base plate having a first side and a second side having a conductive surface. A repository having an internal volume to releasably retain a conductive fluid is disposed on the first side of the base plate. A rupturable membrane is disposed between the internal volume of the repository and the conductive surface of the base plate. A coupling is disposed on the base plate that is configured to detachably engage a gas charge, whereby the gas charge is detachable from the coupling without causing destruction of the gas charge, to provide a hermetic seal with an outlet of the gas charge, and to provide fluid communication between the internal volume of the repository and the outlet of gas charge when the gas charge is engaged by the coupling. A retainer is configured to detachably secure the gas charge to the base plate.

BACKGROUND

The present disclosure is generally directed to systems and methods ofdelivering electrical therapy to a patient.

There are a wide variety of electronic and mechanical devices formonitoring and treating patients' medical conditions. In some examples,depending on the underlying medical condition being monitored ortreated, medical devices such as cardiac monitors or defibrillators maybe surgically implanted or externally connected to the patient. In someexamples, physicians may use medical devices alone or in combinationwith drug therapies to treat conditions such as cardiac arrhythmias.

One of the deadliest cardiac arrhythmias is ventricular fibrillation,which occurs when normal, regular electrical impulses are replaced byirregular and rapid impulses, causing the heart muscle to stop normalcontractions and to begin to quiver. Normal blood flow ceases, and organdamage or death can result in minutes if normal heart contractions arenot restored. Because the victim has no perceptible warning of theimpending fibrillation, death often occurs before the necessary medicalassistance can arrive. Other cardiac arrhythmias can include excessivelyslow heart rates known as bradycardia or excessively fast heart ratesknown as tachycardia. Cardiac arrest can occur when a patient in whichvarious arrhythmias of the heart, such as ventricular fibrillation,ventricular tachycardia, pulseless electrical activity (PEA), andasystole (e.g., heart stops all electrical activity) result in the heartproviding insufficient levels of blood flow to the brain and other vitalorgans for the support of life.

Cardiac arrest and other cardiac health ailments are a major cause ofdeath worldwide. Various resuscitation efforts aim to maintain thebody's circulatory and respiratory systems during cardiac arrest in anattempt to save the life of the patient. The sooner these resuscitationefforts begin, the better the patient's chances of survival. Implantablecardioverter/defibrillators (ICDs) or external defibrillators (such asmanual defibrillators or automated external defibrillators (AEDs)) havesignificantly improved the ability to treat these otherwiselife-threatening conditions. Such devices operate by applying correctiveelectrical pulses directly to the patient's heart. Ventricularfibrillation or ventricular tachycardia can be treated by an implantedor external defibrillator, for example, by providing a therapeutic shockto the heart in an attempt to restore normal rhythm. To treat conditionssuch as bradycardia, an implanted or external pacing device can providepacing stimuli to the patient's heart until intrinsic cardiac electricalactivity returns.

Example external cardiac monitoring and/or treatment devices includecardiac monitors, the ZOLL LifeVest® wearable cardioverter defibrillatoravailable from ZOLL Medical Corporation, and the AED Plus also availablefrom ZOLL Medical Corporation.

Some examples of cardiac monitoring and/or treatment devices includetherapy electrodes that release conductive gel onto the skin of asubject prior to delivering electrical therapy to the subject todecrease electrical resistance between the therapy electrode and thesubject. Such therapy electrodes have in the past been single usedevices that would be replaced after each use with the older devicesbeing discarded.

SUMMARY

In accordance with one aspect, there is provided a therapeutic electrodecomponent for application of electrical stimulus to a subject and forallowing reuse of non-destroyed portions of a therapeutic electrode inapplication of electrical stimulus to a subject. The therapeuticelectrode component comprises a base plate having a first side and asecond side opposing the first side, the second side having a conductivesurface. The therapeutic electrode component further comprises arepository having an internal volume configured to releasably retain aconductive fluid. The repository is disposed on the first side of thebase plate. A rupturable membrane is disposed between the internalvolume of the repository and the conductive surface of the base plate. Acoupling is disposed on the base plate. The coupling is configured todetachably engage a gas charge, whereby the gas charge is detachablefrom the coupling without causing destruction of at least the gascharge, to provide a hermetic seal with an outlet of the gas charge, andto provide fluid communication between the internal volume of therepository and the outlet of gas charge when the gas charge is engagedby the coupling. The therapeutic electrode component further comprises aretainer configured to detachably secure the gas charge to the baseplate.

In some embodiments, the gas charge is detachable from the couplingwithout causing destruction of at least the base plate, the repository,and the rupturable membrane.

In some embodiments, the coupling comprises a barb including an internalpneumatic conduit configured to provide the fluid communication betweenthe internal volume of the repository and the outlet of gas charge whenthe gas charge is engaged by the coupling.

In some embodiments, the therapeutic electrode component furthercomprises a connector formed of a resilient material and including aconduit having a first opening configured to receive and releasablyretain the barb and a second opening configured to receive and retainthe outlet of the gas charge.

In some embodiments, the therapeutic electrode component furthercomprises pneumatic tubing providing fluid communication between theoutlet of the gas charge and the barb.

In some embodiments, the barb extends in a direction parallel to a planedefined by a surface of the first side of the base plate.

In some embodiments, the barb extends in a direction perpendicular to aplane defined by a surface of the first side of the base plate.

In some embodiments, the coupling comprises a snap ring coupled to thefirst side of the base plate. The therapeutic electrode component mayfurther comprise a feed-through including a base that surrounds an endportion of the gas charge and the outlet of the gas charge, and a barbextending from the base that is configured to releasably engage the snapring. The therapeutic electrode component may further comprise an O-ringdisposed between the base and the snap ring when the barb is engagedwith the snap ring and that enhances hermeticity of a seal between thefeed-through and snap ring.

In some embodiments, the therapeutic electrode component furthercomprises a pneumatic header in fluid communication with the outlet ofthe gas charge, the snap ring being configured to receive and releasablyretain the pneumatic header. The therapeutic electrode component mayfurther comprise an O-ring disposed between the snap ring and pneumaticheader when the gas charge is engaged with the coupling and thatenhances hermeticity of a seal between the snap ring and pneumaticheader. The pneumatic header may be retained within a resilient bodycoupled to the gas charge.

In some embodiments, the coupling comprises a feed-though disposed onthe first side of the base plate including a neck defining an internalvolume. The therapeutic electrode component may further comprise awasher formed of a resilient material that surrounds a length of theoutlet of the gas charge and is configured to be retained within theinternal volume of the neck of the feed-thorough, an O-ring surroundingthe neck of the feed-through, and a snap ring that couples to the feedthrough and traps the O-ring between the snap ring and the feed-through.

In some embodiments, the gas charge is disposed within a module that isdetachably engageable with the base plate. The coupling may include apost disposed on the first side of the base plate and including apneumatic conduit configured to provide the fluid communication betweenthe internal volume of the repository and the outlet of gas charge whenthe gas charge is engaged by the coupling. The post may be configured toengage an aperture in the module. The therapeutic electrode componentmay further comprise an O-ring disposed between a neck of the pneumaticconduit and the aperture in the module that enhances hermeticity of aseal between the pneumatic conduit and module. The module may beconfigured to couple to the first side of the base plate by sliding themodule in a plane defined by a surface of the first side of the baseplate into a cradle coupled to the first side of the base plate. Theretainer may include one or more clips disposed on the cradle thatengage one or more slots on the module. The retainer may include one ormore clips disposed on the module that engage one or more slots on thecradle. The retainer may include one or more conductive fasteners thatpass through the base plate and engage one or more respective aperturesin the module. The one or more conductive fasteners may electricallyengage the conductive surface of the base plate when securing the moduleto the base plate. The one or more conductive fasteners may beconfigured to deliver one of a defibrillation pulse or a pacing pulse tothe subject through the conductive surface of the base plate. In someexamples, the defibrillation pulse may include a biphasic current pulseof between about 0 and 150 A. In some embodiments, the therapeuticelectrode component further comprises a circuit board disposed withinthe module and configured to control activation of the gas charge. Thetherapeutic electrode component may further comprise signal leads inelectrical communication between the circuit board and the gas chargeand configured to deliver an activation current to the gas charge. Insome examples, the activation current may be at least 0.1 mA.

In some embodiments, the module is configured to couple to the firstside of the base plate by moving the module in a direction perpendicularto a plane defined by a surface of the first side of the base plate ontothe first side of the base plate.

In some embodiments, the therapeutic electrode component furthercomprises a conduit disposed on the base plate providing fluidcommunication between the coupling and the internal volume of therepository. The rupturable membrane may be configured to ruptureresponsive to delivery of gas from the gas charge to the internal volumeof the repository through the conduit. The repository may be configuredto release the conductive fluid onto the conductive surface of the baseplate responsive to delivery of gas from the gas charge to the internalvolume of the repository through the conduit. The repository maycomprise a plurality of separate chambers each releasably retaining avolume of the conductive fluid and in fluid communication with theconduit.

In accordance with another aspect, there is provided a wearabletherapeutic device for allowing reuse of non-destroyed portions of atherapeutic electrode in application of electrical stimulus to asubject. The device comprises a garment configured to be worn about thesubject, at least one therapeutic electrode component configured to beremovably retained by the garment, circuitry configured to provide atherapeutic pulse of energy to the at least one therapeutic electrodecomponent, and at least one processor operatively coupled to thecircuitry and the at least one therapeutic electrode component. The atleast one therapeutic component comprises a base plate having a firstside and a second side opposing the first side. The second side has aconductive surface. The at least one therapeutic component furthercomprises a repository having an internal volume configured toreleasably retain the conductive fluid. The repository is disposed onthe first side of the base plate. A rupturable membrane is disposedbetween the internal volume of the repository and the conductive surfaceof the base plate. A coupling is disposed on the base plate. Thecoupling is configured to detachably engage a gas charge, whereby thegas charge is detachable from the coupling without causing destructionof at least the gas charge, to provide a hermetic seal with an outlet ofthe gas charge, and to provide fluid communication between the internalvolume of the repository and the outlet of gas charge when the gascharge is engaged by the coupling. The at least one therapeuticcomponent further comprises a retainer configured to detachably securethe gas charge to the base plate.

In accordance with another aspect, there is provided a method fordelivery of electrical stimulus to a subject and allowing reuse ofnon-destroyed portions of a therapeutic electrode in application of theelectrical stimulus to the subject. The method comprises securing a gascharge to a coupling disposed on a first surface of a base plate of atherapeutic electrode component, the coupling providing fluidcommunication with an internal volume of a repository disposed on thebase plate, the repository configured to dispense a conductive fluidonto a conductive second surface of the base plate through a rupturablemembrane disposed between the internal volume of the repository and theconductive surface of the base plate. The method further comprises,responsive to determining that the gas charge should be replaced,removing the gas charge from the coupling without causing destruction toat least the base plate, the repository, and the rupturable membrane,and securing a replacement gas charge to the coupling.

In accordance with another aspect, there is provided a method fordelivery of electrical stimulus to a subject and allowing reuse ofnon-destroyed portions of a therapeutic electrode in delivery of theelectrical stimulus to the subject. The method comprises securing a gascharge to a coupling disposed on a first surface of a base plate of atherapeutic electrode component, the coupling providing fluidcommunication with an internal volume of a repository disposed on thebase plate, the repository configured to dispense a conductive fluidonto a conductive second surface of the base plate through a rupturablemembrane disposed between the internal volume of the repository and theconductive surface of the base plate. The method further comprises,responsive to determining that the gas charge should be moved from thetherapeutic electrode component to a second therapeutic electrodecomponent, removing the gas charge from the coupling without causingdestruction to at least the base plate, the repository, and therupturable membrane, and securing the gas charge to a second coupling ofthe second therapeutic electrode component.

In accordance with another aspect, there is provided a therapeuticelectrode component for application of electrical stimulus to a subjectand for allowing reuse of non-destroyed portions of a therapeuticelectrode in application of electrical stimulus to a subject. Thetherapeutic electrode component comprises a base plate having a firstside and a second side opposing the first side, the second side having aconductive surface. The therapeutic electrode component furthercomprises a repository having an internal volume configured toreleasably retain a conductive fluid. The repository is disposed on thefirst side of the base plate. A rupturable membrane is disposed betweenthe internal volume of the repository and the conductive surface of thebase plate. A coupling is disposed on the base plate. The coupling isconfigured to detachably engage a gas charge. The gas charge isdetachable from the coupling without causing destruction of at least thegas charge and/or the coupling. The coupling provides a hermetic sealwith an outlet of the gas charge, and fluid communication between theinternal volume of the repository and the outlet of gas charge when thegas charge is engaged by the coupling. The therapeutic electrodecomponent further comprises a retainer configured to detachably securethe gas charge to the base plate.

In accordance with another aspect, there is provided a therapeuticelectrode component for application of electrical stimulus to a subjectand for allowing reuse of non-destroyed portions of a therapeuticelectrode in application of electrical stimulus to a subject. Thetherapeutic electrode component comprises a base plate having a firstside and a second side opposing the first side, the second side having aconductive surface, a repository having an internal volume configured toreleasably retain a conductive fluid, the repository disposed on thefirst side of the base plate, a rupturable membrane disposed between theinternal volume of the repository and the conductive surface of the baseplate, a coupling disposed on the base plate, the coupling configured todetachably engage a gas charge, the gas charge being detachable from thecoupling without causing destruction of at least the gas charge, thecoupling further configured to provide a hermetic seal with an outlet ofthe gas charge, and to provide fluid communication between the internalvolume of the repository and the outlet of gas charge when the gascharge is engaged by the coupling, and a retainer configured todetachably secure the gas charge to the base plate.

In some embodiments, the gas charge is detachable from the couplingwithout causing destruction of at least the base plate, the repository,and the rupturable membrane.

In some embodiments, the coupling comprises a barb including an internalpneumatic conduit configured to provide the fluid communication betweenthe internal volume of the repository and the outlet of gas charge whenthe gas charge is engaged by the coupling.

In some embodiments, the therapeutic electrode component furthercomprises a connector formed of a resilient material and including aconduit having a first opening configured to receive and releasablyretain the barb and a second opening configured to receive and retainthe outlet of the gas charge.

In some embodiments, the coupling comprises a snap ring coupled to thefirst side of the base plate, and a pneumatic header in fluidcommunication with the outlet of the gas charge, the snap ring beingconfigured to releasably retain the pneumatic header.

In some embodiments, the pneumatic header is retained within a resilientbody coupled to the gas charge.

In some embodiments, the coupling comprises a feed-though disposed onthe first side of the base plate including a neck defining an internalvolume, a washer formed of a resilient material that surrounds a lengthof the outlet of the gas charge and is configured to be retained withinthe internal volume of the neck of the feed-thorough, an O-ringsurrounding the neck of the feed-through, and a snap ring that couplesto the feed through and traps the O-ring between the snap ring and thefeed-through.

In some embodiments, the gas charge is disposed within a module that isdetachably engageable with the base plate, and the coupling includes apost disposed on the first side of the base plate and including apneumatic conduit configured to provide the fluid communication betweenthe internal volume of the repository and the outlet of gas charge whenthe gas charge is engaged by the coupling, the post configured to engagean aperture in the module.

In some embodiments, the gas charge is disposed within a module that isdetachably engageable with the base plate, and wherein the module isconfigured to couple to the first side of the base plate by sliding themodule in a plane defined by a surface of the first side of the baseplate into a cradle coupled to the first side of the base plate.

In some embodiments, the retainer includes one or more conductivefasteners that pass through the base plate and engage one or morerespective apertures in the module.

In some embodiments, the one or more conductive fasteners electricallyengage the conductive surface of the base plate when securing module tothe base plate.

In some embodiments, the therapeutic electrode component furthercomprises one or more conductive fasteners, the one or more conductivefasteners configured to deliver one of a defibrillation pulse or apacing pulse to the subject through the conductive surface of the baseplate.

In some embodiments, the defibrillation pulse comprises a biphasiccurrent pulse of between about 0 and 150 Amps and the pacing pulsecomprises a current of between about 0 mAmps to about 200 to mAmps.

In some embodiments, the gas charge is disposed within a module that isdetachably engageable with the base plate, and the therapeutic electrodecomponent further comprises a circuit board disposed within the moduleand configured to control activation of the gas charge, and signal leadsin electrical communication between the circuit board and the gas chargeand configured to deliver an activation current to the gas charge.

In some embodiments, the gas charge is disposed within a module that isdetachably engageable with the base plate, the module being configuredto couple to the first side of the base plate by moving the module in adirection perpendicular to a plane defined by a surface of the firstside of the base plate on to the first side of the base plate.

In some embodiments, the therapeutic electrode component furthercomprises a conduit disposed on the base plate providing fluidcommunication between the coupling and the internal volume of therepository.

In some embodiments, the repository comprises a plurality of separatechambers each releasably retaining a volume of the conductive fluid andin fluid communication with the conduit.

In some embodiments, the rupturable membrane is configured to ruptureresponsive to delivery of gas from the gas charge to the internal volumeof the repository through the conduit.

In some embodiments, the repository is configured to release theconductive fluid onto the conductive surface of the base plateresponsive to delivery of gas from the gas charge to the internal volumeof the repository through the conduit.

In accordance with another aspect, there is provided a wearabletherapeutic device for allowing reuse of non-destroyed portions of atherapeutic electrode in application of electrical stimulus to asubject. The wearable therapeutic device comprises a garment configuredto be worn about the subject, at least one therapeutic electrodecomponent configured to be removably retained by the garment, circuitryconfigured to provide a therapeutic pulse of energy to the at least onetherapeutic electrode component, and at least one processor operativelycoupled to the circuitry and the at least one therapeutic electrodecomponent. The at least one therapeutic component comprises a base platehaving a first side and a second side opposing the first side, thesecond side having a conductive surface, a repository having an internalvolume configured to releasably retain the conductive fluid, therepository disposed on the first side of the base plate, a rupturablemembrane disposed between the internal volume of the repository and theconductive surface of the base plate, a coupling disposed on the baseplate, the coupling configured to detachably engage a gas charge, thegas charge being detachable from the coupling without causingdestruction of at least the gas charge, the coupling further configuredto provide a hermetic seal with an outlet of the gas charge, and toprovide fluid communication between the internal volume of therepository and the outlet of gas charge when the gas charge is engagedby the coupling, an a retainer configured to detachably secure the gascharge to the base plate.

In some embodiments, the gas charge is detachable from the couplingwithout causing destruction of at least the base plate, the repository,and the rupturable membrane.

In some embodiments, the wearable therapeutic device further comprisesone or more conductive fasteners, the one or more conductive fastenersconfigured to deliver one of a defibrillation pulse or a pacing pulse tothe subject through the conductive surface of the base plate.

In some embodiments, the defibrillation pulse comprises a biphasiccurrent pulse of between about 0 and 150 Amps and the pacing pulsecomprises a current of between about 0 mAmps to about 200 to mAmps.

In some embodiments, the gas charge is disposed within a module that isdetachably engageable with the base plate, and the therapeutic electrodecomponent further comprises a circuit board disposed within the moduleand configured to control activation of the gas charge, and signal leadsin electrical communication between the circuit board and the gas chargeand configured to deliver an activation current to the gas charge.

In some embodiments, the wearable therapeutic device further comprises aconduit disposed on the base plate providing fluid communication betweenthe coupling and the internal volume of the repository.

In some embodiments, the repository comprises a plurality of separatechambers each releasably retaining a volume of the conductive fluid andin fluid communication with the conduit.

BRIEF DESCRIPTION OF THE DRAWINGS

Various aspects of at least one example are discussed below withreference to the accompanying figures, which are not intended to bedrawn to scale. The figures are included to provide an illustration anda further understanding of the various aspects and examples, and areincorporated in and constitute a part of this specification, but are notintended to limit the scope of the disclosure. The drawings, togetherwith the remainder of the specification, serve to explain principles andoperations of the described and claimed aspects and examples. In thefigures, each identical or nearly identical component that isillustrated in various figures is represented by a like numeral. Forpurposes of clarity, not every component may be labeled in every figure.

FIG. 1 depicts an example of a wearable medical device;

FIG. 2A depicts a first view of a medical device controller for thewearable medical device of FIG. 1 ;

FIG. 2B depicts a second view of a medical device controller for thewearable medical device of FIG. 1 ;

FIG. 2C depicts a component-level view of an example of a medical devicecontroller for the wearable medical device of FIG. 1 ;

FIG. 3 depicts an example of a therapeutic electrode component;

FIG. 4 depicts the therapeutic electrode component of FIG. 3 with amodule including a gas charge and circuit board detached from a baseplate of the therapeutic electrode component;

FIG. 5A depicts the module of the therapeutic electrode component ofFIG. 3 partially disengaged from the base plate;

FIG. 5B depicts the module of the therapeutic electrode component ofFIG. 3 engaged with the base plate;

FIG. 6 depicts a circuit board and gas charge disposed within the moduleof the therapeutic electrode component of FIG. 3 ;

FIG. 7 illustrates a conductive fastener providing electrical connectionbetween a conductive lower surface and the circuit board disposed withinthe module of the therapeutic electrode component of FIG. 3 ;

FIG. 8A depicts another example of a therapeutic electrode component;

FIG. 8B depicts the therapeutic electrode component of FIG. 8A with amodule including a gas charge detached from a base plate of thetherapeutic electrode component;

FIG. 9 depicts a gas charge disposed within the module of thetherapeutic electrode component of FIG. 8A;

FIG. 10 depicts the module of the therapeutic electrode component ofFIG. 8A engaged with a coupling on a base plate of the therapeuticelectrode component;

FIG. 11 depicts an example gel escape hole with a rupturable ring seal;

FIG. 12A depicts another example of a therapeutic electrode component;

FIG. 12B depicts the therapeutic electrode component of FIG. 12A with amodule including a gas charge and circuit board detached from a baseplate of the therapeutic electrode component;

FIG. 13 depicts the module of the therapeutic electrode component ofFIG. 12A engaged with a coupling on a base plate of the therapeuticelectrode component;

FIG. 14A is an enlarged view of the area of engagement of the module ofthe therapeutic electrode component of FIG. 12A with the coupling on thebase plate of the therapeutic electrode component;

FIG. 14B is an enlarged view of the area of engagement of the module ofthe therapeutic electrode component of 12A with the coupling on the baseplate of the therapeutic electrode component with the module beingunengaged with the coupling;

FIG. 15A depicts another example of a therapeutic electrode component;

FIG. 15B depicts the therapeutic electrode component of FIG. 15A with amodule including a gas charge and circuit board detached from the baseplate of the therapeutic electrode component;

FIG. 16A depicts the gas charge and circuit board disposed within themodule of the therapeutic electrode component of FIG. 15A;

FIG. 16B depicts an underside of the module of the therapeutic electrodecomponent of FIG. 15A;

FIG. 16C depicts module of the therapeutic electrode component of FIG.15A disposed on the base plate and the outlet of the gas chargepneumatically connected to a coupling on the base plate.

FIG. 17A depicts another connection mechanism for pneumatically couplinga gas charge to a base plate of a therapeutic electrode component in anexploded view;

FIG. 17B depicts the mechanism of FIG. 17A in an assembled state;

FIG. 18A depicts another connection mechanism for pneumatically couplinga gas charge to a base plate of a therapeutic electrode component;

FIG. 18B depicts the mechanism of FIG. 18A disposed in an example of atherapeutic electrode component; and

FIG. 18C depicts the therapeutic electrode component of FIG. 18B in anassembled state.

DETAILED DESCRIPTION

This disclosure relates to devices, systems and methods for deliveringelectrical therapy to a patient.

Cardiac monitoring and/or treatment devices include therapy electrodecomponents that release conductive fluid or gel onto the skin of asubject prior to delivering electrical therapy. The gel causes adecrease in electrical resistance between the conductive surface of thetherapy electrode and the subject's skin. The deployed gel can helpavoid causing burns on the patient's skin during therapy. Further, thedeployed gel can cause substantially all or most of the current from thetherapeutic electrode components to be delivered to the patient. Inimplementation, the conductive fluid or gel may have a limited shelflife, for example, due to evaporation of liquid from the conductivefluid or gel. For example, such evaporation can occur through the wallsof the receptacle(s) in the therapy electrode components that house theconductive fluid or gel prior to dispensing the fluid or gel. Exampledevices, systems, and methods are described herein to allow for reuse ofnon-destroyed portions of a therapeutic electrode. For example, duringservice, the deteriorated conductive fluid or gel can be removed andremaining therapeutic electrode components can be reused.

As described further below, one of the therapeutic electrode componentsthat is designed herein to be re-used is a gas charge. A gas charge orcartridge is used in some examples of therapy electrode components togenerate pressure to push the conductive fluid or gel out of thereceptacle(s) in the therapy electrode components and onto the skin of apatient to reduce electrical resistance between the therapy electrodecomponents and the patient. The gas cartridge can be, in someimplementations, an expensive component of a therapy electrode.Conventional therapy electrode components including conductive fluid orgel dispensing systems gas cartridges utilizing gas cartridges as asource of pressure to dispense the conductive fluid or gel do notprovide for the gas cartridge to be removed or replaced without damagingthe gas cartridge or other portions of the therapy electrode component.Thus, in instances in which, for example, the conductive fluid or gel ina therapy electrode component reaches or exceeds its shelf life or ifthe therapy electrode component or gas cartridge develops a leak or someother defect that would warrant replacement of the gas cartridge, onecannot remove the gas cartridge and replace it or other portions of thetherapy electrode component. Rather, the entire therapy electrodecomponent, including the gas cartridge, is discarded. Example devices,systems, and methods are described herein to allow for reuse ofnon-destroyed portions of a therapeutic electrode. For example, duringservice, the deteriorated conductive fluid or gel can be removed andremaining therapeutic electrode components can be reused.

Examples of devices and systems for delivering electrical therapy to apatient disclosed herein include a therapeutic electrode component forapplication of electrical stimulus to a subject. The therapeuticelectrode component allows for reuse of non-destroyed portions of atherapeutic electrode in application of electrical stimulus to asubject. In examples, the therapeutic electrode component includes abase plate having a first side and a second side opposing the firstside. The second side of the therapeutic electrode component has aconductive surface that is disposed directly in contact with the skin ofa patient, or indirectly such as through clothing, fabric, and/or aconductive mesh. The conductive surface may be disposed against, forexample, a portion of the chest or back of the patient. Electricaltherapy may be delivered to the patient through the conductive surface.The first side of the base plate includes a repository having aninternal volume configured to releasably retain a conductive fluid thatis expelled onto the skin of the patient and provides a low impedanceelectrical path between the conductive surface of the base plate and theskin of the patient to facilitate the delivery of the electrical therapyto the patient. A rupturable membrane is disposed between the internalvolume of the repository and the conductive surface of the base platewhich ruptures in response to pressure applied to the conductive fluidand allows the conductive fluid to be expelled onto the skin of thepatient.

In implementations herein, a coupling is disposed on the base plate thatallows one to detachably engage a gas charge to the base plate. The gascharge is used to provide the pressure to the conductive fluid when itis desired to expel the conductive fluid onto the skin of the subject.The gas charge is detachable from the coupling without causingdestruction of at least the gas charge so that the gas charge may bereplaced or removed for use with a different therapeutic electrodecomponent. In examples, the coupling provides a hermetic seal with anoutlet of the gas charge to prevent leaks of gas from the gas charge andto direct substantially all gas output from the gas charge to a portionof the therapeutic electrode component where it may apply pressure tothe conductive fluid. The coupling, for example, provides fluidcommunication between the internal volume of the repository and theoutlet of gas charge when the gas charge is engaged by the coupling. Thetherapeutic electrode component includes also includes a retainerconfigured to detachably secure the gas charge to the base plate.

Examples of systems for delivering electrical therapy to a patientdisclosed herein may include a wearable therapeutic device that allowsfor reuse of non-destroyed portions of a therapeutic electrode componentutilized for application of electrical stimulus to a subject. Thewearable therapeutic device includes a garment configured to be wornabout the subject. The garment is designed to removably retain at leastone therapeutic electrode component as described above. The wearabletherapeutic device includes circuitry that is used to provide atherapeutic pulse of energy to the at least one therapeutic electrodecomponent. At least one processor is operatively coupled to thecircuitry and the at least one therapeutic electrode component tocontrol operation of the wearable therapeutic device and circuitry. Theat least one therapeutic electrode component includes a base platehaving a first side and a second side opposing the first side. Thesecond side of the therapeutic electrode component has a conductivesurface that may disposed against the skin of a patient directly, orindirectly such as through clothing, fabric, and/or a conductive mesh,for example, on a portion of the chest or back of the patient, andthough which electrical therapy may be delivered to the patient. Thefirst side of the base plate includes a repository having an internalvolume configured to releasably retain a conductive fluid that isexpelled onto the skin of the patient and provides a low impedanceelectrical path between the conductive surface of the base plate and theskin of the patient to facilitate the delivery of the electrical therapyto the patient. A rupturable membrane is disposed between the internalvolume of the repository and the conductive surface of the base platewhich ruptures in response to pressure applied to the conductive fluidand allows the conductive fluid to be expelled onto the skin of thepatient. A coupling is disposed on the base plate that allows one todetachably engage a gas charge to the base plate. The gas charge is usedto provide the pressure to the conductive fluid when it is desired toexpel the conductive fluid onto the skin of the subject. The gas chargeis detachable from the coupling without causing destruction of at leastthe gas charge so that the gas charge may be replaced or removed for usewith a different therapeutic electrode component. The coupling providesa hermetic seal with an outlet of the gas charge to prevent leaks of gasfrom the gas charge and to direct substantially all gas output from thegas charge to a portion of the therapeutic electrode component where itmay apply pressure to the conductive fluid. The coupling, for example,provides fluid communication between the internal volume of therepository and the outlet of gas charge when the gas charge is engagedby the coupling. The therapeutic electrode component includes alsoincludes a retainer configured to detachably secure the gas charge tothe base plate.

Examples of methods for delivery of electrical stimulus to a subjectdisclosed herein provide for reuse of non-destroyed portions of atherapeutic electrode component used to apply the electrical stimulus tothe subject. In one example, the method includes securing a gas chargeto a coupling disposed on a first surface of a base plate of atherapeutic electrode component. The coupling provides fluidcommunication with an internal volume of a repository disposed on thebase plate. The repository includes conductive fluid which, prior todelivery of the electrical stimulus to the subject, is dispensed onto aconductive second surface of the base plate through a rupturablemembrane disposed between the internal volume of the repository and theconductive surface of the base plate. If one determines that the gascharge should be replaced, for example, due to leakage or for use in adifferent therapeutic electrode component, the gas charge may be removedfrom the coupling without causing destruction to the gas charge, and insome examples, without causing damage to at least the base plate, therepository, and the rupturable membrane. One may then secure areplacement gas charge to the coupling or secure the gas charge to acoupling on a base plate of another therapeutic electrode component.

In another example, a method for delivery of electrical stimulus to asubject that allows for reuse of non-destroyed portions of a therapeuticelectrode component used for delivery of the electrical stimulus to thesubject includes securing a gas charge to a coupling disposed on a firstsurface of a base plate of a therapeutic electrode component. Thecoupling provides fluid communication with an internal volume of arepository disposed on the base plate. The repository is configured todispense a conductive fluid onto a conductive second surface of the baseplate through a rupturable membrane disposed between the internal volumeof the repository and the conductive surface of the base plate. If onedetermines that the gas charge should be replaced, for example, to bemoved from the therapeutic electrode component to a second therapeuticelectrode component, one may remove the gas charge from the couplingwithout causing destruction to at least the base plate, the repository,and the rupturable membrane. One might desire to move the gas chargefrom a first therapeutic electrode component to another, for example ifone the conductive fluid in the first therapeutic component isapproaching or has exceeded its expiration date or if the hermeticity ofthe first therapeutic electrode component is in question and the gascharge is still expected to be useable. The method further includessecuring the gas charge to a second coupling of the second therapeuticelectrode component.

Advantages of various aspects and embodiments disclosed herein providefor the components of a therapy electrode component including aconductive fluid dispensation system to be non-destructivelydisassembled. In a therapy electrode component in which conductive fluidhas expired, portions of the therapy electrode component, for example,the gas cartridge and/or circuit board and/or a module housing same maybe removed, and one or more of these components may be installed onto areplacement base portion of the therapy electrode component includingfresh conductive fluid. In another example, in a therapy electrodecomponent in which the conductive gel and other associated components,for example, the base plate, conductive fluid repository, and rupturablemembrane are all in useable condition, but the gas cartridge or circuitboard are in some way defective, the gas cartridge and/or circuit boardmay be removed and replaced without damaging the base plate, conductivefluid repository, and rupturable membrane. Accordingly, portions oftherapy electrode components may be replaced if desired to provide afunctional therapy electrode component rather than disposing andreplacing the entirety of the therapy electrode component.

Aspects and embodiment disclosed herein thus provide advantages withrespect to cost and with respect to the number of replacement parts auser or supplier may keep on hand to maintain the therapy electrodecomponents of a therapy electrode system of a patient in usable oroptimal condition.

As described above, the teachings of the present disclosure can begenerally applied to external medical monitoring and/or treatmentdevices (e.g., devices that are not completely implanted within thepatient's body). External medical devices can include, for example,ambulatory medical devices that are capable of and designed for movingwith the patient as the patient goes about his or her daily routine. Anexample ambulatory medical device can be a wearable medical device suchas a wearable cardioverter defibrillator (WCD), a wearable cardiacmonitoring device, an in-hospital device such as an in-hospital wearabledefibrillator, a short-term wearable cardiac monitoring and/ortherapeutic device, mobile telemetry devices, and other similar wearablemedical devices.

The wearable medical device can be capable of continuous use by thepatient. In some implementations, the continuous use can besubstantially or nearly continuous in nature. That is, the wearablemedical device may be continuously used, except for sporadic periodsduring which the use temporarily ceases (e.g., while the patient bathes,while the patient is refit with a new and/or a different garment, whilethe battery is charged/changed, while the garment is laundered, etc.).Such substantially or nearly continuous use as described herein maynonetheless qualify as continuous use. For example, the wearable medicaldevice can be configured to be worn by a patient for as many as 24 hoursa day. In some implementations, the patient may remove the wearablemedical device for a short portion of the day (e.g., for half an hour tobathe).

Further, the wearable medical device can be configured as a long term orextended use medical device. Such devices can be configured to be usedby the patient for an extended period of several days, weeks, months, oreven years. In some examples, the wearable medical device can be used bya patient for an extended period of at least one week. In some examples,the wearable medical device can be used by a patient for an extendedperiod of at least 30 days. In some examples, the wearable medicaldevice can be used by a patient for an extended period of at least onemonth. In some examples, the wearable medical device can be used by apatient for an extended period of at least two months. In some examples,the wearable medical device can be used by a patient for an extendedperiod of at least three months. In some examples, the wearable medicaldevice can be used by a patient for an extended period of at least sixmonths. In some examples, the wearable medical device can be used by apatient for an extended period of at least one year. In someimplementations, the extended use can be uninterrupted until a physicianor other caregiver provides specific instruction to the patient to stopuse of the wearable medical device.

Regardless of the extended period of wear, the use of the wearablemedical device can include continuous or nearly continuous wear by thepatient as described above. For example, the continuous use can includecontinuous wear or attachment of the wearable medical device to thepatient, e.g., through one or more of the therapy electrode componentsas described herein, during both periods of monitoring and periods whenthe device may not be monitoring the patient but is otherwise still wornby or otherwise attached to the patient. The wearable medical device canbe configured to continuously monitor the patient for cardiac-relatedinformation (e.g., electrocardiogram (ECG) information, includingarrhythmia information, heart sounds or heart vibrations, etc.) and/ornon-cardiac information (e.g., blood oxygen, the patient's temperature,glucose levels, tissue fluid levels, and/or lung sounds or vibrations).The wearable medical device can carry out its monitoring in periodic oraperiodic time intervals or times. For example, the monitoring duringintervals or times can be triggered by a user action or another event.

As noted above, the wearable medical device can be configured to monitorother physiologic parameters of the patient in addition to cardiacrelated parameters. The wearable medical device can be configured tomonitor, for example, lung vibrations (e.g., using microphones and/oraccelerometers), breath vibrations, sleep related parameters (e.g.,snoring, sleep apnea), tissue fluids (e.g., using radio-frequencytransmitters and sensors), among others.

Other example wearable medical devices include automated cardiacmonitors and/or defibrillators for use in certain specialized conditionsand/or environments such as in combat zones or within emergencyvehicles. Such devices can be configured so that they can be usedimmediately (or substantially immediately) in a life-saving emergency.In some examples, the wearable medical devices described herein can bepacing-enabled, e.g., capable of providing therapeutic pacing pulses tothe patient.

In implementations, an example therapeutic medical device can include anin-hospital continuous monitoring defibrillator and/or pacing device,for example, an in-hospital wearable defibrillator. In such an example,the electrodes can be adhesively attached to the patient's skin. Forexample, the electrodes can include disposable adhesive electrodes. Forexample, the electrodes can include sensing and therapy componentsdisposed on separate sensing and therapy electrode adhesive patches. Insome implementations, both sensing and therapy components can beintegrated and disposed on a same electrode adhesive patch that is thenattached to the patient. In an example implementation, the electrodescan include a front adhesively attachable therapy electrode, a backadhesively attachable therapy electrode, and a plurality of adhesivelyattachable sensing electrodes. For example, the front adhesivelyattachable therapy electrode attaches to the front of the patient'storso to deliver pacing or defibrillating therapy. Similarly, the backadhesively attachable therapy electrode attaches to the back of thepatient's torso. In an example scenario, at least three ECG adhesivelyattachable sensing electrodes can be attached to at least above thepatient's chest near the right arm, above the patient's chest near theleft arm, and towards the bottom of the patient's chest in a mannerprescribed by a trained professional.

A patient being monitored by an in-hospital defibrillator and/or pacingdevice may be confined to a hospital bed or room for a significantamount of time (e.g., 90% or more of the patient's stay in thehospital). As a result, a user interface can be configured to interactwith a user other than the patient, e.g., a nurse, for device-relatedfunctions such as initial device baselining, setting and adjustingpatient parameters, and changing the device batteries.

In implementations, an example of a therapeutic medical device caninclude a short-term continuous monitoring defibrillator and/or pacingdevice, for example, a short-term outpatient wearable defibrillator. Forexample, such a short-term outpatient wearable defibrillator can beprescribed by a physician for patients presenting with syncope. Awearable defibrillator can be configured to monitor patients presentingwith syncope by, e.g., analyzing the patient's cardiac activity foraberrant patterns that can indicate abnormal physiological function. Forexample, such aberrant patterns can occur prior to, during, or after theonset of symptoms. In such an example implementation of the short-termwearable defibrillator, the electrode assembly can be adhesivelyattached to the patient's skin and have a similar configuration as thein-hospital defibrillator described above.

In examples, the device can output a defibrillation therapy in the formof a biphasic pulse of between about 0 and 150 Amps. For example, thebiphasic waveform is a biphasic truncated exponential waveform. Thedevice can be programmed to provide between around 75 joules to around150 joules (±5%) at 20° C. (68° F.) when discharged into a 50 ohmresistive load. In implementations, settings within that range can beprogrammable in 25 joule increments. In an implementation, the devicecan be configured to deliver around 35 Amps for a maximum jouledefibrillating shock delivered into a 50 ohm load. In examples, thedefibrillation shock sequence can include between around 1 pulse toaround 10 pulses. In examples, the sequence can include around 5 pulses.If conversion of the arrhythmia occurs after a shock, the deviceautomatically precludes delivery of remaining shocks in the sequence.With respect to pacing therapy, in implementations, a maximum currentlevel of current waveform may be set to a value between approximately 0mAmps to 200 to mAmps. In examples, a pulse width may be set to a fixedvalue between approximately 0.05 ms to 2 ms. In examples, a frequency ofthe pulses may be set to a fixed value between approximately 30 pulsesper minute (PPM) to approximately 200 PPM. In accordance with oneimplementation, a 40 ms square wave pulse may be used.

FIG. 1 illustrates an example of a medical device 100 that is external,ambulatory, and wearable by a patient 102, and configured to implementone or more configurations described herein. For example, the medicaldevice 100 can be a non-invasive medical device configured to be locatedsubstantially external to the patient. Such a medical device 100 can be,for example, an ambulatory medical device that is capable of anddesigned for moving with the patient as the patient goes about his orher daily routine. For example, the medical device 100 as describedherein can be bodily-attached to the patient such as the LifeVest®wearable cardioverter defibrillator available from ZOLL® MedicalCorporation. In one example scenario, such wearable defibrillators canbe worn nearly continuously or substantially continuously for two tothree months at a time. During the period of time in which it is worn bythe patient, the wearable defibrillator can be configured tocontinuously or substantially continuously monitor the vital signs ofthe patient and, upon determination that treatment is required, can beconfigured to deliver one or more therapeutic electrical pulses to thepatient. For example, such therapeutic shocks can be pacing,defibrillation, or transcutaneous electrical nerve stimulation (TENS)pulses.

The medical device 100 can include one or more of the following: agarment 110, one or more sensing electrodes 112 (e.g., ECG electrodes),one or more therapy electrodes 114, a medical device controller 120, aconnection pod 130, a patient interface pod 140, a belt, or anycombination of these. In some examples, at least some of the componentsof the medical device 100 can be configured to be affixed to the garment110 (or in some examples, permanently integrated into the garment 110),which can be worn about the patient's torso.

The medical device controller 120 can be operatively coupled to thesensing electrodes 112, which can be affixed to the garment 110, e.g.,assembled into the garment 110 or removably attached to the garment,e.g., using hook and loop fasteners. In some implementations, thesensing electrodes 112 can be permanently integrated into the garment110. The medical device controller 120 can be operatively coupled to thetherapy electrodes 114. For example, the therapy electrodes 114 can alsobe assembled into the garment 110, or, in some implementations, thetherapy electrodes 114 can be permanently integrated into the garment110.

Component configurations other than those shown in FIG. 1 are possible.For example, the sensing electrodes 112 can be configured to be attachedat various positions about the body of the patient 102. The sensingelectrodes 112 can be operatively coupled to the medical devicecontroller 120 through the connection pod 130. In some implementations,the sensing electrodes 112 can be adhesively attached to the patient102. In some implementations, the sensing electrodes 112 and at leastone of the therapy electrodes 114 can be included on a single integratedpatch and adhesively applied to the patient's body.

The sensing electrodes 112 can be configured to detect one or morecardiac signals. Examples of such signals include ECG signals and/orother sensed cardiac physiological signals from the patient. In certainimplementations, the sensing electrodes 112 can include additionalcomponents such as accelerometers, acoustic signal detecting devices,and other measuring devices for recording additional parameters. Forexample, the sensing electrodes 112 can also be configured to detectother types of patient physiological parameters and acoustic signals,such as tissue fluid levels, heart vibrations, lung vibrations,respiration vibrations, patient movement, etc. Example sensingelectrodes 112 include a metal electrode with an oxide coating such astantalum pentoxide electrodes, as described in, for example, U.S. Pat.No. 6,253,099 titled “Cardiac Monitoring Electrode Apparatus andMethod,” the content of which is incorporated herein by reference.

In some examples, the therapy electrodes 114 can also be configured toinclude sensors configured to detect ECG signals as well as otherphysiological signals of the patient. The connection pod 130 can, insome examples, include a signal processor configured to amplify, filter,and digitize these cardiac signals prior to transmitting the cardiacsignals to the medical device controller 120. One or more of the therapyelectrodes 114 can be configured to deliver one or more therapeuticdefibrillating shocks to the body of the patient 102 when the medicaldevice 100 determines that such treatment is warranted based on thesignals detected by the sensing electrodes 112 and processed by themedical device controller 120. Example therapy electrodes 114 caninclude conductive metal electrodes such as stainless-steel electrodesthat include, in certain implementations, one or more conductive geldeployment devices configured to deliver conductive gel to the metalelectrode prior to delivery of a therapeutic shock.

In some implementations, medical devices as described herein can beconfigured to switch between a therapeutic medical device and amonitoring medical device that is configured to only monitor a patient(e.g., not provide or perform any therapeutic functions). For example,therapeutic components such as the therapy electrodes 114 and associatedcircuitry can be optionally decoupled from (or coupled to) or switchedout of (or switched in to) the medical device. For example, a medicaldevice can have optional therapeutic elements (e.g., defibrillationand/or pacing electrodes, components, and associated circuitry) that areconfigured to operate in a therapeutic mode. The optional therapeuticelements can be physically decoupled from the medical device to convertthe therapeutic medical device into a monitoring medical device for aspecific use (e.g., for operating in a monitoring-only mode) or apatient.

Alternatively, the optional therapeutic elements can be deactivated(e.g., by a physical or a software switch), essentially rendering thetherapeutic medical device a monitoring medical device for a specificphysiologic purpose or a particular patient. As an example of a softwareswitch, an authorized person can access a protected user interface ofthe medical device and select a preconfigured option or perform someother user action via the user interface to deactivate the therapeuticelements of the medical device.

FIGS. 2A-B illustrate an example medical device controller 120. Forexample, the controller 120 includes a connector receptacle 201 forconnecting the sensing and/or therapy electrode components to thecontroller 120. The controller 120 includes a speaker 203 for providingaudio prompts to the patient and/or a bystander. The controller 120includes circuitry as further described below with reference to FIG. 3 .The circuitry is housed within a mechanical housing structure 205 toprotect the circuitry and other internal components of the controller120 from physical damage, particle ingress, and/or water ingress. Thecontroller includes one or more response buttons 211 a, 211 b. A patientwearing the wearable medical device can communicate with the controller120 via the buttons 211 a, 211 b. For example, if the device detects alife-threatening arrhythmia condition in the patient, the controller 120can direct the patient to press the one or more buttons 211 a, 211 b. Insome examples, the controller 120 can include a display screen 221. Forexample, the display screen 221 can be a touch-sensitive panel screenresponsive to patient input in the form of touch or physical forceapplied to the screen. For example, the display screen 221 can displaycontrols and/or prompts to the patient, and is responsive to thepatient's touch or application of physical force on the displayedcontrols. The controller 120 can be powered by a removable battery 210(see FIG. 2C below) that is housed within a battery chamber 223.

FIG. 2C illustrates a sample component-level view of the medical devicecontroller 120 of the medical device 100 of FIG. 1 . As shown in FIG.2C, the medical device controller 120 can include a therapy deliveryinterface circuit 202, a data storage 204, a network interface 206, auser interface 208, at least one battery 210, a sensor interface 212, auser interface/alarm manager 214, and least one processor 218.

The therapy delivery interface circuit 202 can be coupled to one or moreelectrodes 220 configured to provide therapy to the patient (e.g.,therapy electrodes 114 as described above in connection with FIG. 1 ).For example, the therapy delivery interface circuit 202 can include, orbe operably connected to, circuitry components that are configured togenerate and provide the therapeutic shock. The circuitry components caninclude, for example, resistors, capacitors, relays and/or switches,electrical bridges such as an H-bridge (e.g., including a plurality ofinsulated gate bipolar transistors or IGBTs), voltage and/or currentmeasuring components, and other similar circuitry components arrangedand connected such that the circuitry components work in concert withthe therapy delivery circuit and under control of one or more processors(e.g., processor 218) to provide, for example, one or more pacing ordefibrillation therapeutic pulses.

Pacing pulses can be used to treat cardiac arrhythmias such asbradycardia (e.g., less than 30 beats per minute) and tachycardia (e.g.,more than 150 beats per minute) using, for example, fixed rate pacing,demand pacing, anti-tachycardia pacing, and the like. Defibrillationpulses can be used to treat ventricular tachycardia and/or ventricularfibrillation.

The capacitors can include a parallel-connected capacitor bankconsisting of a plurality of capacitors (e.g., two, three, four or morecapacitors). These capacitors can be switched into a series connectionduring discharge for a defibrillation pulse. For example, fourcapacitors of approximately 650 uF can be used. The capacitors can havebetween 350 to 500 volt surge rating and can be charged in approximately15 to 30 seconds from a battery pack.

For example, each defibrillation pulse can deliver between 60 to 180joules of energy. In some implementations, the defibrillating pulse canbe a biphasic truncated exponential waveform, whereby the signal canswitch between a positive and a negative portion (e.g., chargedirections). This type of waveform can be effective at defibrillatingpatients at lower energy levels when compared to other types ofdefibrillation pulses (e.g., such as monophasic pulses). For example, anamplitude and a width of the two phases of the energy waveform can beautomatically adjusted to deliver a precise energy amount (e.g., 150joules) regardless of the patient's body impedance. The therapy deliveryinterface circuit 202 can be configured to perform the switching andpulse delivery operations, e.g., under control of the processor 218. Asthe energy is delivered to the patient, the amount of energy beingdelivered can be tracked. For example, the amount of energy can be keptto a predetermined constant value even as the pulse waveform isdynamically controlled based on factors such as the patient's bodyimpedance to which the pulse is being delivered.

The data storage 204 can include one or more of non-transitory computerreadable media, such as flash memory, solid state memory, magneticmemory, optical memory, cache memory, combinations thereof, and others.The data storage 204 can be configured to store executable instructionsand data used for operation of the medical device controller 120. Incertain implementations, the data storage can include executableinstructions that, when executed, are configured to cause the at leastone processor 218 to perform one or more functions.

In some examples, the network interface 206 can facilitate thecommunication of information between the medical device controller 120and one or more other devices or entities over a communications network.For example, where the medical device controller 120 is included in anambulatory medical device (such as medical device 100), the networkinterface 206 can be configured to communicate with a remote computingdevice such as a remote server or other similar computing device. Thenetwork interface 206 can include communications circuitry fortransmitting data in accordance with a Bluetooth® wireless standard forexchanging such data over short distances to an intermediary device(s)(e.g., a base station, a “hotspot” device, a smartphone, a tablet, aportable computing device, and/or other devices in proximity of thewearable medical device 100). The intermediary device(s) may in turncommunicate the data to a remote server over a broadband cellularnetwork communications link. The communications link may implementbroadband cellular technology (e.g., 2.5G, 2.75G, 3G, 4G, 5G cellularstandards) and/or Long-Term Evolution (LTE) technology or GSM/EDGE andUMTS/HSPA technologies for high-speed wireless communication. In someimplementations, the intermediary device(s) may communicate with aremote server over a Wi-Fi™ communications link based on the IEEE 802.11standard.

In certain implementations, the user interface 208 can include one ormore physical interface devices such as input devices, output devices,and combination input/output devices and a software stack configured todrive operation of the devices. These user interface elements may rendervisual, audio, and/or tactile content. Thus, the user interface 208 mayreceive input or provide output, thereby enabling a user to interactwith the medical device controller 120.

The medical device controller 120 can also include at least one battery210 configured to provide power to one or more components integrated inthe medical device controller 120. The battery 210 can include arechargeable multi-cell battery pack. In one example implementation, thebattery 210 can include three or more 2200 mAh lithium ion cells thatprovide electrical power to the other device components within themedical device controller 120. For example, the battery 210 can provideits power output in a range of between 20 mA to 1000 mA (e.g., 40 mA)output and can support 24 hours, 48 hours, 72 hours, or more, of runtimebetween charges. In certain implementations, the battery capacity,runtime, and type (e.g., lithium ion, nickel-cadmium, or nickel-metalhydride) can be changed to best fit the specific application of themedical device controller 120.

The sensor interface 212 can be coupled to one or more sensorsconfigured to monitor one or more physiological parameters of thepatient. As shown, the sensors may be coupled to the medical devicecontroller 120 via a wired or wireless connection. The sensors caninclude one or more electrocardiogram (ECG) electrodes 222 (e.g.,similar to sensing electrodes 112 as described above in connection withFIG. 1 ).

The ECG electrodes 222 can monitor a patient's ECG information. Forexample, the ECG electrodes 222 can be galvanic (e.g., conductive)and/or capacitive electrodes configured to measure changes in apatient's electrophysiology to measure the patient's ECG information.The ECG electrodes 222 can transmit information descriptive of the ECGsignals to the sensor interface 212 for subsequent analysis.

The sensor interface 212 can be coupled to any one or combination ofsensing electrodes/other sensors to receive other patient dataindicative of patient parameters. Once data from the sensors has beenreceived by the sensor interface 212, the data can be directed by the atleast one processor 218 to an appropriate component within the medicaldevice controller 120. For example, if ECG data is collected by sensingelectrode 222 and transmitted to the sensor interface 212, the sensorinterface 212 can transmit the data to the at least one processor 218which, in turn, relays the data to a cardiac event detector. The cardiacevent data can also be stored on the data storage 204.

In certain implementations, the user interface/alarm manager 214 can beconfigured to manage alarm profiles and notify one or more intendedrecipients of events specified within the alarm profiles as being ofinterest to the intended recipients. These intended recipients caninclude external entities such as users (patients, physicians, andmonitoring personnel) as well as computer systems (monitoring systems oremergency response systems). The user interface/alarm manager 214 can beimplemented using hardware or a combination of hardware and software.For instance, in some examples, the user interface/alarm manager 214 canbe implemented as a software component that is stored within the datastorage 204 and executed by the at least one processor 218. In thisexample, the instructions included in the alarm manager 214 can causethe at least one processor 218 to configure alarm profiles and notifyintended recipients using the alarm profiles. In other examples, alarmmanager 214 can be an application-specific integrated circuit (ASIC)that is coupled to the at least one processor 218 and configured tomanage alarm profiles and notify intended recipients using alarmsspecified within the alarm profiles. Thus, examples of alarm manager 214are not limited to a particular hardware or software implementation.

In some implementations, the at least one processor 218 includes one ormore processors (or one or more processor cores) that each areconfigured to perform a series of instructions that result inmanipulated data and/or control the operation of the other components ofthe medical device controller 120. In some implementations, whenexecuting a specific process (e.g., cardiac monitoring), the at leastone processor 218 can be configured to make specific logic-baseddeterminations based on input data received, and be further configuredto provide one or more outputs that can be used to control or otherwiseinform subsequent processing to be carried out by the at least oneprocessor 218 and/or other processors or circuitry with which the atleast one processor 218 is communicatively coupled. Thus, the at leastone processor 218 reacts to specific input stimulus in a specific wayand generates a corresponding output based on that input stimulus. Insome examples, the at least one processor 218 can proceed through asequence of logical transitions in which various internal registerstates and/or other bit cell states internal or external to the at leastone processor 218 may be set to logic high or logic low. As referred toherein, the at least one processor 218 can be configured to execute afunction where software is stored in a data store coupled to the atleast one processor 218, the software being configured to cause the atleast one processor 218 to proceed through a sequence of various logicdecisions that result in the function being executed. The variouscomponents that are described herein as being executable by the at leastone processor 218 can be implemented in various forms of specializedhardware, software, or a combination thereof. For example, the processorcan be a digital signal processor (DSP) such as a 24-bit DSP processor.The at least one processor can be or include a multi-core processor,e.g., having two or more processing cores. The processor can be anAdvanced RISC Machine (ARM) processor such as a 32-bit ARM processor.The at least one processor can execute an embedded operating system, andinclude services provided by the operating system that can be used forfile system manipulation, display and audio generation, basicnetworking, firewalling, data encryption and communications.

One embodiment of a therapeutic electrode component is illustrated inFIGS. 3-7 , indicated generally as 300. The therapeutic electrodecomponent 300 includes a base plate 305 having a first side 305A and asecond side 305B opposing the first side. The second side 305B includesa conductive surface 410 (see FIG. 7 ). One or more repositories 310,ten in the embodiment illustrated in FIGS. 3-7 , are disposed on thefirst side 305A of the base plate 305. The repositories 310 have aninternal volume that releasably retains a conductive fluid 315.

Referring briefly to FIG. 11 , a rupturable membrane 340, e.g., in theform of a rupturable ring seal, is disposed between the internal volumeof each repository 310 and the conductive surface 410 of the base plate305. When the rupturable membrane 340 is ruptured, the fluid 315 flowsfrom the internal volume on to the conductive surface 410 via the fluidor gel escape hole 343. The respective rupturable membranes 340associated with each respective repository 310 are configured to ruptureresponsive to pressure being applied to the internal volumes of therepositories 310 so that the conductive fluid 315 can flow out of therepositories 310 and onto the conductive surface 410 of the second side305B of the base plate 305. Each repository 310 is associated with afluid or gel escape hole 343 to allow for the fluid or gel to escape onto the conductive surface.

Referring back to FIGS. 3-7 , a conduit 320 is disposed on the baseplate 305. The conduit 320 is in fluid communication between theinternal volumes of each repository 310 and a coupling 330 (see FIG. 4). The conduit 320 includes a central portion 320A and branches 320Bleading to each respective repository 310. The conduit provides forfluid to flow from the coupling 330 to the internal volumes of therepositories 310 to pressurize the internal volumes of the repositories310 and cause the rupturable membrane 340 to rupture and the conductivefluid 315 to be pushed out of the repositories 310 through the rupturedrupturable membrane 340 via the fluid or gel escape holes 343.

A removable module 325 is detachably engageable with the base plate 305.As illustrated in FIGS. 5A-7 , the module 325 houses a gas charge 365and a circuit board 385. The gas charge 365 is a source of pressurizedgas that, when the gas charge 365 is activated, causes gas to flowthrough the coupling 330 and conduit 320 to pressurize the internalvolumes of the repositories 310 and cause the conductive fluid 315 to bedispensed. The circuit board 385 provides communication with an externalcontroller, for example, medical device controller 120 illustrated inFIGS. 1, 2A, and 2B, and controls activation of the gas charge 365 anddelivery of electrical therapy to a patient.

The therapeutic electrode component 300 is illustrated in FIG. 4 withthe module 325 removed. As illustrated in FIG. 4 , a cradle 335 iscoupled to the first side 305A of the base plate 305. The cradle 335 issized and shaped to releasably retain the removable module 325. Thecradle 335 includes a retainer that detachably engages the module 325.In the embodiment illustrated in FIG. 4 the retainer is in the form ofclips 345 that releasably engage slots 350 (see FIG. 5A) on the module325. In other embodiments, the clips 345 may be included on the module325 and the slots 350 on the cradle.

Also visible in FIG. 4 is the coupling 330. The coupling 330 includes abarb 355 having an internal pneumatic conduit 360 (see FIGS. 5A, 5B)that provides fluid communication between the internal volumes of therepositories 310 and the outlet of gas charge 365 via the conduit 320when the gas charge 365 is engaged by the coupling 330. In theembodiment illustrated in FIG. 4 , the barb 355 extends in a directionparallel to a plane defined by the first side 305A of the base plate305.

FIGS. 5A and 5B illustrate the module 325 disposed on the cradle 335 andwithout its top cover. In FIG. 5A the clips 345 of the cradle are notengaged with the slots 350 on the module. If the module 325 is slid tothe left in a plane defined by the surface of the first side 305A of thebase plate 305 from the position shown in FIG. 5A to that shown in FIG.5B, the clips 345 engage the slots 350 to retain the module 325 in thecradle 335. The slots 350 of the module 325 are not visible in FIG. 5Bbecause they are underneath the clips 345.

Disposed within the module 325 is the gas charge 365. The gas charge 365may be fixed in place in the module 325 by, for example, an adhesive orone or more fasteners. A connector 370 formed of a resilient material,for example, rubber includes a conduit 375 that has a first opening 375Athat engages the barb 355 of the coupling 330 when the module 325 is inthe engaged position illustrated in FIG. 5B. The conduit 375 of theconnector 370 also has a second opening 375B that receives and retainsan outlet 380 of the gas charge 365. The coupling 330 engages the gascharge 365 via the connector 370. The gas charge 365 may be detachedfrom the coupling 330 by sliding the module 325 from the positionillustrated in FIG. 5B to the position illustrated in FIG. 5A. When thegas charge 365 is engaged with the coupling 330 the coupling 330provides a hermetic seal with the outlet 380 of the gas charge 365 andprovides fluid communication between the internal volumes of therepositories 310 and the outlet 380 of gas charge 365.

A circuit board 385 is also disposed within the removable module 325, asillustrated in FIG. 6 . As discussed above, the circuit board 385provides communication with an external controller, for example, medicaldevice controller 120 illustrated in FIGS. 1, 2A, and 2B, and controlsactivation of the gas charge 365 and delivery of electrical therapy to apatient through the conductive surface 410 of the base plate 305 of thetherapeutic electrode component 300. An electrical signal lead 390extends from the circuit board to the gas cartridge 365 for providing anactivation current to the gas charge 365. One or more apertures 395including or surrounded by an electrical contact is provided in thecircuit board 385 for outputting electrical pulses to be delivered to apatient for electrical therapy. In examples, the activation current canbe at least 0.1 mA. In some applications, the activation current can bein a range from between around 0.1 mA to around 1 A. In animplementation, the activation current can be between around 0.01 A toaround 0.3 A. For example, the activation current comprises a pulse ofbetween around 1 ms and 75 seconds. In examples, the activation currentcomprises a pulse of around 10 ms to around 30 seconds. An operatingrange in which the above activation current parameters were tested isbetween around −25 F and 160 F.

The therapeutic electrode component 300 further includes one or moreconductive fasteners 405, as illustrated in FIG. 7 , that engage or passthrough the one or more apertures 395 in the circuit board 385, throughone or more aperture 397A in the module 325, and through one or moreaperture 397B in the base plate 305. One or more of the apertures 395,397A, 397B may be threaded to facilitate retention of the conductivefastener or fasteners 405. The conductive fastener or fasteners 405makes an electrical connection with the electrical contact of theaperture 395 of the circuit board 385 on a first end and makes anelectrical connection with the conductive surface 410 of the base plate305 of the therapeutic electrode component 300 on a second end. Theconductive fastener or fasteners 405 thus provide electricalcommunication between the circuit board 385 and the conductive surface410 of the base plate 305 of the therapeutic electrode component 300.The conductive fastener or fasteners 405 is configured to deliver one ofa defibrillation pulse or a pacing pulse to a subject through theconductive surface 410 of the base plate 305. The conductive fastener orfasteners 405 also secure the module 325 in place in the cradle 335 onthe base plate 305. The one or more conductive fasteners 405electrically engage the conductive surface 410 of the base plate 305when securing module 325 to the base plate 305.

Another embodiment of a therapeutic electrode component is illustratedin FIGS. 8A-10 , indicated generally at 900. The therapeutic electrodecomponent 900 includes many of the same features as the therapeuticelectrode component 300. Features of the therapeutic electrode component900 that are similar to those of the therapeutic electrode component 300are indicated with similar reference numbers as used for the therapeuticelectrode component 300 but with the reference numbers beginning with a“9” instead of a “3.” The therapeutic electrode component 900 includes,for example, a base plate 905 having a first side 905A and a second side905B opposing the first side that corresponds with the base plate 305 ofthe therapeutic electrode component 300. The second side 905B includes aconductive surface 1010 (see FIG. 10 ) corresponding to the conductivesurface 410 of the therapeutic electrode component 300. The therapeuticelectrode component 900 includes repositories 910 corresponding to therepositories 310 of the therapeutic electrode component 300 disposed onthe first side 905A of the base plate 905. The repositories 910 have aninternal volume that releasably retains a conductive fluid 915,corresponding to the conductive fluid 315 of the therapeutic electrodecomponent 300. The conductive fluid 915 is releasably retained withinthe internal volumes of the repositories by rupturable membranescorresponding to the rupturable membranes 340 of the therapeuticelectrode component 300. The therapeutic electrode component 900 furtherincludes a conduit 920 disposed on the base plate 905 that correspondsto the conduit 320 and has a central portion 920A and branches 920B,corresponding to the central portion 320A and branches 320B of thetherapeutic electrode component 300.

The module of the therapeutic electrode component 900 includes a firstportion 925A that is fixed to the base plate 905 and that includes acircuit board corresponding to the circuit board 385 of the therapeuticelectrode component 300. The circuit board of the therapeutic electrodecomponent 900 is electrically coupled to the conductive surface 1010 ofthe second side 905B of the base plate 905 of the therapeutic electrodecomponent 900, for example, with one or more conductive fastenerscorresponding to the one or more conductive fasteners 405 of thetherapeutic electrode component 300.

A second portion 925B of the module of the therapeutic electrodecomponent 900 includes a gas charge 965 corresponding to the gas charge365 of the therapeutic electrode component 300. The second portion 925Bof the module is detachably engageable with the base plate 905 and witha coupling 930 that that provides fluid communication between theinternal volumes of the repositories 910 and the outlet of gas charge965 via the conduit 920 when the gas charge 965 is engaged by thecoupling 930. The second portion 925B of the module includes one or moretabs or clips 945 that releasably engage one or more apertures or slots950 in walls 952 coupled to the base plate 905, and optionally formedintegral with the first portion 925A, that define a cradle for thesecond portion and that removably retain the second portion 925B on thebase plate 905.

As illustrated in FIG. 9 , the second portion 925B of the module retainsa gas cartridge 965 that includes an electrical signal lead 990 thatelectrically connects the circuit board (e.g., similar to circuit board385 of FIG. 6 ) within the first portion 925A of the module to the gascartridge 965 for providing an activation current to the gas charge 965.The signal lead 990 can be connected to the circuit board via solderpads. For example, an electrical connection between the signal lead 990and circuit board components can be made through a two-positionconnector. For example, a two-position connector can include awire-to-wire connector with leads on one side going connected to the gascartridge 965, and leads on the other side of the connector coupled tosolder pads on the circuit board. An end of the gas cartridge 965including the output of the gas cartridge 965 is engaged by a resilientbody 970 formed of a resilient material, for example, rubber. Theresilient body 970 includes a recess 972, for example, a cylindricallyshaped recess in fluid communication with the outlet of the gascartridge 965.

As shown in further detail in FIG. 10 , the coupling 930 includes apneumatic header 934 that is in fluid communication with the outlet ofthe gas charge 965 via the connector 970. The pneumatic header 934 isreceived within the resilient body 970 coupled to the gas charge 965.The pneumatic header 934 is fixed to and inseparable from the base plate905. In such an implementation, the resilient body 970 slides down overthe pneumatic header making a radial seal when the gas charge 965 isinstalled.

The pneumatic header 934 includes an external side wall or walls 932that are sealed to an internal wall or walls 974 of the recess 972 ofthe resilient body 970. In some implementations, an adhesive isdispersed within the internal wall or walls 974 of the recess 972 andthe external side wall or walls 932 of the pneumatic header 934.

The pneumatic header 934 includes an internal fluid conduit 960 forflowing gas released from the gas charge 965 into the conduit 920. Thecoupling 930 also includes a snap ring 936 that is coupled to the firstside 905A of the base plate 905. The snap ring 936 may be disposed andretained in place below a layer of plastic material 908 that covers thefirst side 905A of the base plate 905 and the repositories 910. In animplementation, the snap ring 936 is a fixed to and inseparable from thebase plate 905. In an implementation, the snap ring 936 is sized andshaped to receive and releasably retain the pneumatic header 934. AnO-ring 938 is disposed between the snap ring 936 and pneumatic header934 when the gas charge 965 is engaged with the coupling 930 andenhances hermeticity of a seal between the snap ring 936 and pneumaticheader 934. In an example, the snap ring 936 stays with the base platewhen the second portion 925B is removed. In some examples, both the snapring 936 and the O-ring 938 stay with the base plate when the secondportion 925B is removed.

Another embodiment of a therapeutic electrode component is illustratedin FIGS. 12A-14B, indicated generally at 1200. The therapeutic electrodecomponent 1200 includes many of the same features as the therapeuticelectrode component 300. Features of the therapeutic electrode component1200 that are similar to those of the therapeutic electrode component300 are indicated with similar reference numbers as used for thetherapeutic electrode component 300 but with the reference numbersbeginning with a “12” instead of a “3.” The therapeutic electrodecomponent 1200 includes, for example, a base plate 1205 having a firstside 1205A and a second side 1205B opposing the first side thatcorresponds with the base plate 305 of the therapeutic electrodecomponent 300. The second side 1205B includes a conductive surface 1310corresponding to the conductive surface 410 of the therapeutic electrodecomponent 300. The therapeutic electrode component 1200 includesrepositories 1210 corresponding to the repositories 310 of thetherapeutic electrode component 300 disposed on the first side 1205A ofthe base plate 1205. The repositories 1210 have internal volumes thatreleasably retain a conductive fluid 1215, corresponding to theconductive fluid 315 of the therapeutic electrode component 300. Theconductive fluid 1215 is releasably retained within the internal volumesof the repositories by rupturable membranes corresponding to therupturable membranes 340 of the therapeutic electrode component 300. Thetherapeutic electrode component 1200 further includes a conduit 1220disposed on the base plate 1205 that corresponds to the conduit 320 andhas a central portion 1220A and branches 1220B, corresponding to thecentral portion 320A and branches 320B of the therapeutic electrodecomponent 300.

A removable module 1225 is detachably engageable with the base plate1205. The module 1225 houses a gas charge 1265 and a circuit board 1285,corresponding to the gas charge 365 and circuit board 385, respectively,of the therapeutic electrode component 300. The gas cartridge 1265 thatincludes an electrical signal lead 1290 that electrically connects thecircuit board 1285 within the module 1225 to the gas cartridge 1265 forproviding an activation current to the gas charge 1265. The module 1225is illustrated without a cover to show the gas charge 1265 and circuitboard 1285 contained within, but in use, would include a cover. When themodule 1225 is removably secured to the base plate 1205, the circuitboard 1285 of the therapeutic electrode component 1200 may beelectrically coupled to the conductive surface 1310 of the second side1205B of the base plate 1205 of the therapeutic electrode component1200, for example, with one or more conductive fasteners correspondingto the one or more conductive fasteners 405 of the therapeutic electrodecomponent 300.

The module 1225 is detachably engageable with the base plate 1205 andfrom a coupling 1230 that that provides fluid communication between theinternal volumes of the repositories 1210 and the outlet of gas charge1265 via the conduit 1220 when the gas charge 1265 is engaged by thecoupling 1230. The therapeutic electrode component 1200 is illustratedin FIG. 12B with the module 1225 removed and the coupling 1230 visible.The module 1225 is removed and placed onto the base plate 1205 bypulling or pushing the module 1225 in a direction normal to a planedefined by the first side 1205A or second side 1205B of the base plate1205. Installing or removing the module 1225 from the base plate 1205causes an aperture 1275 in a lower surface 1225B of the module 1225 toengage or disengage the coupling 1230.

As illustrated in further detail in FIGS. 13, 14A, and 14B, the coupling1230 includes a post 1234 disposed on the first side 1205A of the baseplate 1205 and including a pneumatic conduit 1260 configured to providethe fluid communication between the internal volume of the repositories1210 and the outlet of gas charge 1265 when the gas charge 1265 isengaged by the coupling 1230. The post 1234 is sized and shaped toengage the aperture 1275 in the module 1225. The post 1234 may include aflange portion that is disposed below and retained in place by a layerof plastic material 1208 that covers the first side 1205A of the baseplate 1205 and the repositories 1210. An O-ring 1238 is disposed betweena neck of the pneumatic conduit 1260 defined in the post 1234 and theaperture 1275 in the module 1225. The O-ring 1238 enhances hermeticityof a seal between the pneumatic conduit 126 defined in the post 1234 andmodule 1225.

The module 1225 can be secured to the base plate 1205 with one or morescrews. For example, the one or more screws can include threaded insertsor self-tapping screws. In examples, the module 1225 can be secured tothe base plate 1205 with screws that are inserted from the conductiveside of the base plate 1205 and pass through the layers of the baseplate 1205 and tighten into corresponding screw bosses in the module1225.

Another embodiment of a therapeutic electrode component is illustratedin FIGS. 15A-16C, indicated generally at 1500. The therapeutic electrodecomponent 1500 includes many of the same features as the therapeuticelectrode component 300. Features of the therapeutic electrode component1500 that are similar to those of the therapeutic electrode component300 are indicated with similar reference numbers as used for thetherapeutic electrode component 300 but with the reference numbersbeginning with a “15” instead of a “3.” The therapeutic electrodecomponent 1500 includes, for example, a base plate 1505 having a firstside 1505A and a second side 1505B opposing the first side thatcorresponds with the base plate 305 of the therapeutic electrodecomponent 300. The second side 1505B includes a conductive surface 1610corresponding to the conductive surface 410 of the therapeutic electrodecomponent 300. The therapeutic electrode component 1500 includesrepositories 1510 corresponding to the repositories 310 of thetherapeutic electrode component 300 disposed on the first side 1505A ofthe base plate 1505. The repositories 1510 have internal volumes thatreleasably retain a conductive fluid 1515, corresponding to theconductive fluid 315 of the therapeutic electrode component 300. Theconductive fluid 1515 is releasably retained within the internal volumesof the repositories by rupturable membranes corresponding to therupturable membranes 340 of the therapeutic electrode component 300. Thetherapeutic electrode component 1500 further includes a conduit 1520disposed on the base plate 1505 that corresponds to the conduit 320 andhas a central portion 1520A and branches 1520B, corresponding to thecentral portion 320A and branches 320B of the therapeutic electrodecomponent 300.

The therapeutic electrode component 1500 includes a module 1525detachably engaged with the base plate 1505. The module 1525 includes afirst body 1525A and a second body 1525B. As illustrated in FIGS. 16Aand 16C, the first body 1525A houses a gas charge 1565 and a circuitboard 1585 which correspond to the gas charge 365 and circuit board 385of the therapeutic electrode component 300.

The therapeutic electrode component 1500 is illustrated in FIG. 15B withthe module 1525 removed. As illustrated in FIG. 15B, a cradle 1535 iscoupled to the first side 1505A of the base plate 1505. The cradle 1535is sized and shaped to releasably retain the removable module 1525. Thecradle 1535 includes a retainer that detachably engages the module 1525.In the embodiment illustrated in FIG. 15B the retainer is in the form ofclips 1545 that releasably engage recesses 1550 (see FIGS. 16A, 16B) onthe module 1525. To engage the module 1525 with the cradle 1535 and baseplate 1505, the module 1525 is pushed downward in a direction normal toa plane defined by the base plate 1505 into the cradle 1535 until theclips 1545 of the cradle 1535 engage the recesses 1550 of the module1525. The module 1525 may be removed from the cradle 1535 and base plate1505 by pulling upward on the module 1525 with sufficient force to causethe clips 1545 of the cradle 1535 to disengage the recesses 1550 of themodule 1525 and release the module 1525 from the cradle 1535. In otherembodiments, the clips 1545 may be included on the module 1525 and therecesses 1550 on the cradle clips. A portion of the conduit 1520 may beformed by a channel defined in the cradle 1535.

Also visible in FIGS. 15B and 16C is a coupling 1530. The coupling 1530includes a barb 1555 that provides fluid communication between theinternal volumes of the repositories 1510 and the outlet of gas charge1565 via the conduit 1520 when the gas charge 1565 is engaged by thecoupling 1530. In the embodiment illustrated in FIGS. 15B and 16C, thebarb 355 extends in a direction parallel to a plane defined by the firstside 305A of the base plate 305. The module 1525 may be removed andreplaced from the cradle 1535 and base plate 1505 without damaging thecoupling 1530.

As illustrated in FIGS. 16B and 16C, an outlet 1580 of the gas charge1565 extends through a wall 1525D separating an internal volume of thefirst body 1525A of the module 1525 from a chamber 1525C defined in thesecond body 1525B of the module 1525. A short length of pneumatic tubing1570 engages the barb 1555 of the coupling 1530 and the outlet 1580 ofthe gas charge 1565 and provides fluid communication between theinternal volumes of the repositories 1510 and the outlet 1580 of gascharge 1565 via the coupling 1530 and conduit 1520.

The circuit board 1585 includes one or more apertures 1595,corresponding to the one or more apertures 395 of the therapeuticelectrode component 300, that include or are surrounded by an electricalcontact for outputting electrical pulses to be delivered to a patientfor electrical therapy. One or more conductive fasteners, correspondingto the one or more conductive fasteners 405 of the therapeutic electrodecomponent 300, may engage or pass through the one or more apertures 1595in the circuit board 1585, through one or more aperture 1597 in thecradle 1535, one or more apertures (not shown) in the module 1525, andthrough one or more apertures (not shown) in the base plate 1505. One ormore of the apertures in the circuit board 1585, base plate 1505, and/ormodule 1525 may be threaded to facilitate retention of the conductivefastener or fasteners. The conductive fastener or fasteners makes anelectrical connection with the electrical contact of the aperture 1595of the circuit board 1585 on a first end and makes an electricalconnection with the conductive surface 1610 of the base plate 1505 ofthe therapeutic electrode component 1500 on a second end. The conductivefastener or fasteners thus provide electrical communication between thecircuit board 1585 and the conductive surface 1610 of the base plate1505 of the therapeutic electrode component 300. The conductive fasteneror fasteners is configured to deliver one of a defibrillation pulse or apacing pulse to a subject through the conductive surface 1610 of thebase plate 1505. The conductive fastener or fasteners may also helpsecure the module 1525 in place in the cradle 1535 on the base plate1505. The one or more conductive fasteners electrically engage theconductive surface 1610 of the base plate 1505 when securing module 1525to the base plate 1505.

Another example of a coupling for pneumatically connecting a gas chargeto a conduit in fluid communication with internal volumes of one or morerepositories in a therapeutic electrode component as disclosed herein isillustrated in FIGS. 17A and 17B, indicated generally at 1700. Thecoupling 1700 is illustrated along with a gas charge 1775 having anoutlet 1780 in the form of a tube, for example, a stainless steel tube,in an exploded view in FIG. 17A, and in an assembled view in FIG. 17B.The coupling includes a feed-through 1705 that has a neck 1710 definingan interior volume 1715. The feed-through 1705 also includes an aperture1720 to provide fluid communication between the gas charge 1775 and oneor more conductive fluid repositories via a conduit of a therapeuticelectrode component as disclosed herein. An O-ring 1725 fits around andsurrounds the neck 1710 of the feed-through 1705. The coupling 1700further includes a washer 1730 formed of a resilient material thatsurrounds a length of the outlet 1780 of the gas charge 1775 and isconfigured to be retained within the internal volume 1715 of the neck1710 of the feed-thorough 1705. A snap ring 1735 couples to the feedthrough 1705 and traps the O-ring 1725 between the snap ring 1735 andthe feed-through 1705. The internal wall of the neck 1710 of thefeed-through 1705 may compress the washer 1730 to facilitate forming ahermetic seal between the outlet 1780 of the gas charge 1775 and theaperture 1720 of the feed-through 1705. The snap ring 1735 may compressthe neck 1710 of the feed-through 1705 to help compress the washer 1730.In some embodiments, the coupling 1700 may be secured to a base plate1805 of a therapeutic electrode component as disclosed herein by aplastic film 1810 that covers the O-ring 1725 and flange portion 1740 ofthe feed-through 1705.

Another example of a coupling for pneumatically connecting a gas chargeto a conduit in fluid communication with internal volumes of one or morerepositories in a therapeutic electrode component as disclosed herein isillustrated in FIG. 18A, indicated generally at 1900. The coupling 1900includes a snap ring 1905 coupled to the first side of the base plate2005 of a therapeutic electrode component as disclosed herein. The snapring 1905 may be secured to the base plate 2005 by a layer of plasticmaterial 2010 that covers the surface of the base plate 2005. Thecoupling 1900 also includes a feed-through 1910 including a base 1910Athat surrounds an end portion of the gas charge 2065 and the outlet 2080of the gas charge 2065, and a barb 1910B extending from the base 1910Athat is configured to releasably engage the snap ring 1905. An O-ring1915 is disposed between the base 1910A and the snap ring 1905 when thebarb 1910B is engaged with the snap ring 1905. The O-ring 1915 enhanceshermeticity of a seal between the feed-through 1910 and snap ring 1905.A second O-ring 1915 may be disposed on an inner wall or in a recessedregion of the base 1910A to facilitate forming a hermetic seal betweenthe gas charge 2065 and the feed-through 1910.

When sealing with O-rings in the manner described herein, a hermeticseal is achieved. An O-ring is a doughnut-shaped object or torus. Inapplication, the opposite sides of an O-ring are squeezed between thewalls of the space into which the O-ring is installed. The resultingzero clearance within the space provides an effective seal, blocking theflow of liquids or gases through the space's internal passage. An O-ringis typically defined by its dimensions (e.g., based on inside holediameter, ID, and cross section), durometer (Shore A hardness), andmaterial composition. For example, the O-ring can be from any of thefollowing materials. In implementations herein, the O-ring installationincorporates initial O-ring compression. At atmospheric pressure, theinherent resiliency of the compressed O-ring provides the seal. Assystem pressure activates the seal, the O-ring is forced to the lowpressure side of the space. Designed to deform, the O-ring thus fill thediametrical clearance and blocks leakage to form the hermetic seal. Forexample, the O-ring can be Buna-N/Nitrile rubber, a copolymer ofbutadiene and acrylonitrile. Nitrile combines resistance topetroleum-based oils and fuels, silicone greases, hydraulic fluids,water and alcohols. It has a low compression set, high tensile strengthand high abrasion resistance. The O-ring can be made from a compound inthe ethylene-propylene (EPM/EPDM) family. Such materials feature goodresistance to such polar solvents as ketones (e.g., acetone). EPM/EPDMis resistant to steam (e.g., up to 400° F.), hot water, silicone oilsand greases, dilute acids and alkalis, alcohols and automotive brakefluids. Ethylene propylene can provide extended temperature range ofaround −76° F. to around +350° F. The O-ring can be made from a compoundin the silicone family. Silicone material is resistant to high, dryheat. Silicones are fungus resistant, odorless, tasteless, non-toxicelastomers and possess high-resistance to the aging effects of bothsunlight and ozone. The O-ring can be made from a compound in theneoprene family. Neoprene features moderate resistance to petroleumoils, good resistance to ozone, sunlight and oxygen aging, relativelylow compression set, good resilience, reasonable cost, and highresistance to ammonia. The O-ring can be made from a compound in thefluorocarbon family. Such materials can combine high-temperatureresistance with wide chemical agent compatibility. Fluorocarboncompounds feature good resistance to petroleum products and solvents andgood high-temperature compression set characteristics. The O-ring can bemade from a compound in the flurosilicone family. Such materials combinethe good high and low temperature stability of silicones with the fuel,oil and solvent resistance of fluorocarbons. These compounds featuregood compression set and resilience properties. The compounds aresuitable for exposure to air, sunlight, ozone, chlorinated and aromatichydrocarbons. For example, the O-rings are standard AS-568 sizes(Aerospace Size Standard for O-rings from the Society of AutomotiveEngineers).

In examples, the hermetic seal as described herein can be tested in afollowing manner. For example, the test as described herein can becarried out as an engineering or validation testing of therapy electrodecomponents containing a detachable gas generator. For example, failureanalysis testing on units returned from the field can be tested byinserting a hypodermic needle through the laminate into the air channeland sealing around the entrance point with a cyanoacrylate adhesive. Thehypodermic needle can then be attached to a regulated air source. Thetherapy electrode can be placed into a container filled with water.Using the regulator, the air pressure can be increased until a leak isdetected.

In examples, a Pass/Fail test can be used for production. For example, aburst test for the pressurized receptacles can be set to determine thatthe receptacles can withstand pressures of at least between 40 psi and60 psi. For example, a burst test for the pressurized receptacles can beset to a maximum of at least 60 psi. For example, a burst test for thepressurized receptacles can be set to a maximum of at least 50 psi. Forexample, a burst test for the pressurized receptacles can be set to amaximum of at least 50 psi.

In examples, a potential production/service test for therapy electrodecomponents containing a detachable gas generator can be as follows. Asealable port or, in some examples, the same port that the detachablegas generator interfaces with the receptacles can serve as the testport. A ring-seal test can be performed where the base plate laminatecan be pressurized to at least 12 psi for a prescribed period of time, 3seconds, before releasing the pressure. This test can help eliminateweak ring seals that could potentially leak in the field. Inimplementations, the 12 psi pressure supply can be introduced for 3seconds and then the supply can be cut off to monitor for a period oftime, between 15-30 seconds, for a pressure drop. A pressure drop canindicate a leak. After this period has ended, the pressure can bereleased.

FIG. 18B illustrates an example of a therapeutic electrode component2000 including a gas charge 2065 coupled to the therapeutic electrodecomponent 2000 with a coupling 1900 as illustrated in FIG. 18A. In FIG.18B, a feed-through 1910 of the coupling 1900 is visible. The gas charge2065 and a circuit board 2085 are disposed in a cavity 2025 defined inan end of the therapeutic electrode component 2000. A lid 2015 is usedto cover the cavity 2025 in the therapeutic electrode component 2000.The lid 2020 includes a retainer 2020, which functions to keep the gascharge from becoming mechanically disengaged (e.g., prevent the gascharge from “popping out”) when activated. For example, the retainer2020 can mechanically engage with the gas charge 2065 when the lid 2015is secured. In an implementation, the retainer 2020 can be positionedover the gas charge 2065 to reduce movement of the gas charge 2065within the cavity 2025 and further keep it from becoming mechanicallydisengaged when activated. FIG. 18C illustrates the therapeuticelectrode component 2000 with the lid 2015 attached.

In a first example use case, a user wears a wearable therapeutic deviceincluding a garment as illustrated in FIG. 1 and multiple therapeuticelectrode components 300 as illustrated in FIGS. 3-7 removably disposedwithin the garment. The user receives a notification, either from thecontroller of the wearable therapeutic device or from a provider of thewearable therapeutic device, that the conductive fluid in one or more ofthe therapeutic electrode components 300 has reached its expirationdate. The user acquires one or more new base plates includingreceptacles filled with fresh conductive fluid and including theconduit, cradle, and coupling as illustrated in FIG. 4 . The userremoves the conductive fastener or fasteners from the one or moretherapeutic electrode components that have expired conductive fluid andslides the respective modules including the respective gas charges andcircuit boards out of the respective cradles. The user then slides therespective modules including the respective gas charges and circuitboards into the cradles of the replacement base plate sand secures themodules in the cradles with the one or more conductive fasteners. Theuser then replaces the one or more therapeutic electrode componentsincluding the replacement base plates back into their respectivelocations in the garment. The old base plates with the expiredconductive fluid may be discarded or returned to the provider.

A similar use case to the first example use case described above wouldapply to a user who wears a wearable therapeutic device including agarment as illustrated in FIG. 1 and multiple therapeutic electrodecomponents 1200 as illustrated in FIGS. 12A-14B or multiple therapeuticelectrode components 1500 as illustrated in FIGS. 15A-16C removablydisposed within the garment. A difference would be that the user removesand replaces the module by lifting the module off of the base plate andreplaces the module on the base plate via movement of the module in adirection normal to a plane defined by the first or second surfaces ofthe base plate. If the user wears a wearable therapeutic deviceincluding therapeutic electrode components 1500 the user woulddisconnect the pneumatic tubing 1570 prior to removing the module fromthe old base plate and would disengage the clips 1545 from the module toallow it to be removed. The user would press the module into the cradleof the replacement base plate until the clips of the cradle of thereplacement base plate engage the module. The user would reconnect thepneumatic tubing between the coupling of the replacement base plate andthe outlet of the gas cartridge in the module prior to placing thetherapeutic electrode component with the replacement base plate backinto the garment.

In a second example use case, a user again wears a wearable therapeuticdevice including a garment as illustrated in FIG. 1 and multipletherapeutic electrode components 300 as illustrated in FIGS. 3-7removably disposed within the garment. The user receives a notification,for example, from the provider of the wearable therapeutic device thatone or more of the gas charges in one or more of the therapeuticelectrode components disposed in the garment have been discovered tobelong to a batch that has been experiencing failures, for example,failures to release gas after receiving an activation current. Theprovider sends the user one or more replacement modules includingcircuit boards and gas charges from a different batch. The user removesthe conductive fastener or fasteners from the one or more therapeuticelectrode components that have the suspected bad gas charges and slidesthe respective old modules out of the respective cradles. The user thenslides the new modules including the replacement gas charges and circuitboards into the respective cradles of the base plates of the respectivetherapeutic electrode components and secures the modules in the cradleswith the one or more conductive fasteners. The user then replaces theone or more therapeutic electrode components including the replacementmodules back into their respective locations in the garment. The oldmodules with the suspected bad gas charges may be discarded or returnedto the provider.

A similar use case to the second example use case described above wouldapply to a user who wears a wearable therapeutic device including agarment as illustrated in FIG. 1 and multiple therapeutic electrodecomponents 1200 as illustrated in FIGS. 12A-14B or multiple therapeuticelectrode components 1500 as illustrated in FIGS. 15A-16C removablydisposed within the garment. A difference would be that the user removesand replaces the module by lifting the module off of the base plate andreplaces the module on the base plate via movement of the module in adirection normal to a plane defined by the first or second surfaces ofthe base plate. If the user wears a wearable therapeutic deviceincluding therapeutic electrode components 1500 the user woulddisconnect the pneumatic tubing 1570 prior to removing the old modulefrom the old base plate and would disengage the clips 1545 from the oldmodule to allow it to be removed. The user would press the new moduleinto the cradle until the clips engage the new module. The user wouldreconnect the pneumatic tubing between the coupling and the outlet ofthe gas cartridge in the new module prior to placing the therapeuticelectrode component with the new module back into the garment.

In a third example use case, the user may wear a wearable therapeuticdevice including a garment as illustrated in FIG. 1 and multipletherapeutic electrode components 900 as illustrated in FIGS. 8A-10removably disposed within the garment. In the therapeutic electrodecomponents 900 the removable module includes a gas charge, but not acircuit board. In a situation similar to that described in the firstexample use case above, the user would receive a replacement base plate(or more than one) including receptacles filled with fresh conductivefluid and including the conduit, cradle, module first portion 925Aincluding a new circuit board, and coupling as illustrated in FIG. 8B.The user removes the therapeutic electrode component including theexpired conductive fluid from the garment, lifts the module secondportion 925B including the gas charge out of cradle of the oldtherapeutic electrode component, and presses the module second portion925B into the cradle of the replacement base plate until the one or moretabs or clips 945 on the module engage the one or more apertures orslots 950 in the walls 952 coupled to the base plate 905. The user thenreplaces the therapeutic electrode component including the replacementbase plate and old module second portion 925B into the garment.

In a fourth example use case, the user may wear a wearable therapeuticdevice including a garment as illustrated in FIG. 1 and multipletherapeutic electrode components 900 as illustrated in FIGS. 8A-10removably disposed within the garment. In the therapeutic electrodecomponents 900 the removable module includes a gas charge, but not acircuit board. In a situation similar to that described in the secondexample use case above, the user would receive a replacement module (ormore than one) including a circuit board and gas charge from a differentbatch. The user removes the therapeutic electrode component includingthe suspect gas charge from the garment, lifts the module second portion925B including the suspect gas charge out of cradle of the oldtherapeutic electrode component, and presses the replacement modulesecond portion 925B into the cradle of the base plate until the one ormore tabs or clips 945 on the module engage the one or more apertures orslots 950 in the walls 952 coupled to the base plate 905. The user thenreplaces the therapeutic electrode component including the replacementgas charge and old base plate into the garment.

It should be appreciated that in any of the example use cases describedabove, the user of the medical device may be capable of performing thereplacement of the portions of the therapy electrode component(s). Inother examples, these operations may be performed by a provider of themedical device, for example, by the user sending a wearable medicaldevice including one or more of the therapy electrode components to aprovider for service or refurbishment.

Although the subject matter contained herein has been described indetail for the purpose of illustration, it is to be understood that suchdetail is solely for that purpose and that the present disclosure is notlimited to the disclosed embodiments, but, on the contrary, is intendedto cover modifications and equivalent arrangements that are within thespirit and scope of the appended claims. For example, it is to beunderstood that the present disclosure contemplates that, to the extentpossible, one or more features of any embodiment can be combined withone or more features of any other embodiment.

Other examples are within the scope and spirit of the description andclaims. Additionally, certain functions described above can beimplemented using software, hardware, firmware, hardwiring, orcombinations of any of these. Features implementing functions can alsobe physically located at various positions, including being distributedsuch that portions of functions are implemented at different physicallocations.

1-37. (canceled)
 38. A therapeutic electrode component comprising: asource of conductive fluid disposed on a first side of the therapeuticelectrode component and configured to releasably retain a conductivefluid to be expelled onto skin of a patient and provide a low impedanceelectrical path between the therapeutic electrode component and the skinof the patient to facilitate delivery of electrical therapy to thepatient; a non-destructively removable module detachably engageable withthe first side of the therapeutic electrode component and with acoupling disposed on the first side of the therapeutic electrodecomponent, the module housing a source of pressurized gas which whenactivated pressurizes the source of conductive fluid and causes theconductive fluid to be dispensed, the coupling providing fluidcommunication between the source of conductive fluid and the source ofpressurized gas; and a cradle disposed on the first side of thetherapeutic electrode component and configured to detachably engage themodule.
 39. The therapeutic electrode component of claim 38, wherein themodule further houses a circuit board configured to control activationof the source of pressurized gas.
 40. The therapeutic electrodecomponent of claim 39, wherein the circuit board is further configuredto control delivery of the electrical therapy to the patient.
 41. Thetherapeutic electrode component of claim 40, further comprising aconductive fastener that passes through the module and provideselectrical communication between the circuit board and a conductivesurface on a second side of the therapeutic electrode component.
 42. Thetherapeutic electrode component of claim 41, wherein the conductivefastener secures the module in place in the cradle.
 43. The therapeuticelectrode component of claim 38, wherein the module and the cradleinclude complimentary clips and slots which releasable retain the modulewithin the cradle.
 44. The therapeutic electrode component of claim 43,wherein motion of the module in a direction parallel to the first sideof the therapeutic electrode component causes the complimentary clipsand slots to engage or disengage.
 45. The therapeutic electrodecomponent of claim 38, further comprising a conduit providing fluidcommunication between the coupling and the source of conductive fluid.46. The therapeutic electrode component of claim 45, wherein thecoupling includes a barb having an internal pneumatic conduit thatprovides fluid communication between the source of conductive fluid andthe source of pressurized gas via the conduit.
 47. The therapeuticelectrode component of claim 46, wherein the barb extends in a directionparallel to the first side of the therapeutic electrode component. 48.The therapeutic electrode component of claim 47, wherein the modulefurther includes a connector formed of a resilient material having aconduit with a first opening which engages the barb and a second openingwhich engages and forms a hermetic seal with the source of pressurizedgas.
 49. The therapeutic electrode component of claim 38, wherein themodule includes a first portion housing a circuit board configured tocontrol activation of the source of pressurized gas and a separatesecond portion housing the source of pressurized gas.
 50. Thetherapeutic electrode component of claim 49, wherein the second portionof the housing includes a resilient body that engages the source ofpressurized gas and that includes a recess which is in fluidcommunication with the source of pressurized gas and which seals with apneumatic header of the coupling.
 51. The therapeutic electrodecomponent of claim 49, wherein the recess of the resilient body engagesthe pneumatic header of the coupling when the second portion of thehousing is moved downward onto the coupling in a direction normal to thefirst side of the therapeutic electrode component.
 52. A therapeuticelectrode component comprising: a source of conductive fluid disposed ona first side of the therapeutic electrode component and configured toreleasably retain a conductive fluid to be expelled onto skin of apatient and provide a low impedance electrical path between thetherapeutic electrode component and the skin of the patient tofacilitate the delivery of the electrical therapy to the patient; and anon-destructively removable module detachably engageable with the firstside of the therapeutic electrode component and with a coupling disposedon the first side of the therapeutic electrode component, the removablemodule housing a source of pressurized gas which when activatedpressurizes the source of conductive fluid and causes the conductivefluid to be dispensed, the coupling providing fluid communicationbetween the source of conductive fluid and the source of pressurizedgas.
 53. The therapeutic electrode component of claim 52, wherein themodule further houses a circuit board configured to control activationof the source of pressurized gas.
 54. The therapeutic electrodecomponent of claim 53, wherein the module includes a first body housingthe source of pressurized gas and the circuit board, and a second bodyseparated from the first body by a wall, an outlet of the source ofpressurized gas extending through the wall, pneumatic tubing disposedwithin the second body providing fluid communication between the outletof the source of pressurized gas and the coupling.
 55. The therapeuticelectrode component of claim 53, further comprising a conductivefastener that passes through the module and provides electricalcommunication between the circuit board and a conductive surface on asecond side of the therapeutic electrode component.
 56. The therapeuticelectrode component of claim 55, wherein the conductive fastener securesthe module in place on the first side of the therapeutic electrodecomponent.
 57. The therapeutic electrode component of claim 52, whereinan aperture defined in a lower surface of the module engages thecoupling.